25 dead, 101 hurt in Mexico oil company blast

Firefighters belonging to the Tacubaya sector and workers dig for survivors after an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. A large explosion occurred in the lower floors of the building and dozens have been reported injured so far. (AP Photo/Guillermo Gutierrez)
— AP

Firefighters belonging to the Tacubaya sector and workers dig for survivors after an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. A large explosion occurred in the lower floors of the building and dozens have been reported injured so far. (AP Photo/Guillermo Gutierrez)
/ AP

An injured person is carried into an ambulance after an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. An explosion at the main headquarters of Mexico's state-owned oil company in the capital killed more than 10 people and injured some 80 as it heavily damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline. (AP Photo/Eduardo Verdugo)— AP

An injured person is carried into an ambulance after an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. An explosion at the main headquarters of Mexico's state-owned oil company in the capital killed more than 10 people and injured some 80 as it heavily damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline. (AP Photo/Eduardo Verdugo)
/ AP

Rescue workers and firefighters gather at the site of an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. An explosion at the main headquarters of Mexico's state-owned oil company in the capital killed more than 10 people and injured some 80 as it heavily damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline. (AP Photo/Eduardo Verdugo)— AP

Rescue workers and firefighters gather at the site of an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. An explosion at the main headquarters of Mexico's state-owned oil company in the capital killed more than 10 people and injured some 80 as it heavily damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline. (AP Photo/Eduardo Verdugo)
/ AP

Emergency responders walk toward the site on an explosion at a building part of Mexico's state-owned oil company PEMEX complex, in Mexico City, Thursday Jan. 31, 2013. The explosion killed more than 10 people and injured some 80 as it heavily damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline. (AP Photo/Eduardo Verdugo)— AP

Emergency responders walk toward the site on an explosion at a building part of Mexico's state-owned oil company PEMEX complex, in Mexico City, Thursday Jan. 31, 2013. The explosion killed more than 10 people and injured some 80 as it heavily damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline. (AP Photo/Eduardo Verdugo)
/ AP

An emergency responder walks with a search dog as emergency workers and firefighters search for trapped survivors at the site on an explosion in a building at Mexico's state-owned oil company PEMEX complex, in Mexico City, Thursday Jan. 31, 2013. The explosion killed more than 10 people and injured some 80 as it heavily damaged three floors of the building. According to civil protection and local media some people remained trapped in the debris from the explosion, which occurred in the basement of an administrative building next to the iconic, 52-story tower of Petroleos Mexicanos, or PEMEX.(AP Photo/Eduardo Verdugo)— AP

An emergency responder walks with a search dog as emergency workers and firefighters search for trapped survivors at the site on an explosion in a building at Mexico's state-owned oil company PEMEX complex, in Mexico City, Thursday Jan. 31, 2013. The explosion killed more than 10 people and injured some 80 as it heavily damaged three floors of the building. According to civil protection and local media some people remained trapped in the debris from the explosion, which occurred in the basement of an administrative building next to the iconic, 52-story tower of Petroleos Mexicanos, or PEMEX.(AP Photo/Eduardo Verdugo)
/ AP

ALTERNATIVE CROP OF MXEV102.- Rescue workers and firefighters gather as emergency responders search for trapped survivors at the site on an explosion in a building at Mexico's state-owned oil company PEMEX complex, in Mexico City, Thursday Jan. 31, 2013. The explosion killed more than 10 people and injured some 80 as it heavily damaged three floors of the building. According to civil protection and local media some people remained trapped in the debris from the explosion, which occurred in the basement of an administrative building next to the iconic, 52-story tower of Petroleos Mexicanos, or PEMEX.(AP Photo/Eduardo Verdugo)— AP

ALTERNATIVE CROP OF MXEV102.- Rescue workers and firefighters gather as emergency responders search for trapped survivors at the site on an explosion in a building at Mexico's state-owned oil company PEMEX complex, in Mexico City, Thursday Jan. 31, 2013. The explosion killed more than 10 people and injured some 80 as it heavily damaged three floors of the building. According to civil protection and local media some people remained trapped in the debris from the explosion, which occurred in the basement of an administrative building next to the iconic, 52-story tower of Petroleos Mexicanos, or PEMEX.(AP Photo/Eduardo Verdugo)
/ AP

A worker belonging to Mexico's state-owned oil company PEMEX keeps journalists away after an explosion at an adjacent building to the executive tower of PEMEX in Mexico City, Thursday Jan. 31, 2013. An explosion at the main headquarters of Mexico's state-owned oil company in the capital Thursday left at least several workers injured, blew out windows and damaged the building, the company said. (AP Photo/Eduardo Verdugo)— AP

A worker belonging to Mexico's state-owned oil company PEMEX keeps journalists away after an explosion at an adjacent building to the executive tower of PEMEX in Mexico City, Thursday Jan. 31, 2013. An explosion at the main headquarters of Mexico's state-owned oil company in the capital Thursday left at least several workers injured, blew out windows and damaged the building, the company said. (AP Photo/Eduardo Verdugo)
/ AP

Firefighters belonging to the Tacubaya sector and workers dig for survivors after an explosion at a building adjacent to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. A large explosion occurred in the lower floors of the building and dozens have been reported injured so far. (AP Photo/Guillermo Gutierrez)— AP

Firefighters belonging to the Tacubaya sector and workers dig for survivors after an explosion at a building adjacent to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. A large explosion occurred in the lower floors of the building and dozens have been reported injured so far. (AP Photo/Guillermo Gutierrez)
/ AP

Firefighters belonging to the Tacubaya sector and emergency responders pull out a survivor after an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. A large explosion occurred in the lower floors of the building and dozens have been reported injured so far. (AP Photo/Guillermo Gutierrez)— AP

Firefighters belonging to the Tacubaya sector and emergency responders pull out a survivor after an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. A large explosion occurred in the lower floors of the building and dozens have been reported injured so far. (AP Photo/Guillermo Gutierrez)
/ AP

An emergency worker treats an injured worker of Mexico's state-owned oil company PEMEX after an explosion at an adjacent building to the executive tower of PEMEX in Mexico City, Thursday Jan. 31, 2013. A large explosion occurred in the lower floors of the building and dozens have been reported injured so far. (AP Photo/Guillermo Gutierrez)— AP

An emergency worker treats an injured worker of Mexico's state-owned oil company PEMEX after an explosion at an adjacent building to the executive tower of PEMEX in Mexico City, Thursday Jan. 31, 2013. A large explosion occurred in the lower floors of the building and dozens have been reported injured so far. (AP Photo/Guillermo Gutierrez)
/ AP

An emergency responder carries a piece of concrete as emergency workers and firefighter dig for survivor at the site on an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. The explosion killed more than 10 people and injured some 80 as it heavily damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline. (AP Photo/Eduardo Verdugo)— AP

An emergency responder carries a piece of concrete as emergency workers and firefighter dig for survivor at the site on an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City, Thursday Jan. 31, 2013. The explosion killed more than 10 people and injured some 80 as it heavily damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline. (AP Photo/Eduardo Verdugo)
/ AP

MEXICO CITY 
An explosion at the office headquarters of Mexico's state-owned oil company killed 25 people and injured 101 on Thursday as it heavily damaged three floors of a building, sending hundreds into the streets and a large plume of smoke over Mexico City's skyline.

Rescuers continued to search the rubble for victims trapped in the debris late Thursday with the aid of rescue dogs, trucks with mounted lights and an oil company crane. Interior Minister Miguel Osorio Chong said it was uncertain if there were any people still trapped but that crews would keep searching. Many of the office workers were outside having lunch when the explosion occurred about 3:45 p.m. local time in a basement parking garage next to the iconic, 51-story tower of Petroleos Mexicanos, or Pemex, one of the tallest buildings in Mexico City.

Osorio Chong said the explosion hit the basement and first two floors, which rescuers said had collapsed.

"It was an explosion, a shock, the lights went out and suddenly there was a lot of debris," employee Cristian Obele told Milenio television, adding that he had been injured in the leg. "Co-workers helped us get out of the building."

President Enrique Pena Nieto said authorities have not yet found what caused the blast in the 14-story building in a busy commercial and residential area. Pemex first said it had evacuated the building because of a problem with the electrical system. The company later tweeted that the Attorney General's Office was investigating the explosion and any reports of a cause were speculation.

Ana Vargas Palacio was distraught as she searched for her missing husband, Daniel Garcia Garcia, 36, who works in the building where the explosion occurred. She said she last talked to him a couple hours earlier.

"I called his phone many times, but a young man answered and told me he found the phone in the debris," Vargas said. The two have an 11-year-old daughter. His mother, Gloria Garcia Castaneda, collapsed on a friend's arm, crying "My son. My son."

The tower, where several thousand people work, was evacuated following the blast but not damaged, according to Gabriela Espinoza, 50, a Pemex secretary for 29 years who was on the second floor when the explosion next door occurred.

"There was a very loud roar. It was very ugly," she said.

Espinoza's co-worker, Tomas Rivera, 32, worked on the ground floor and was knocked to floor, fracturing his wrist and jaw.

Hundreds of firefighters, military in camouflage and Red Cross workers hauled large chunks of concrete and looked for victims late into the night, with at least four bodies pulled out of the rubble, according to an Associated Press reporter at the scene.

The exploded building was intact on the outside but filled inside with debris.

Television images showed people being evacuated in office chairs, and on gurneys. Most of them had injuries likely caused by falling debris.

"We were talking and all of sudden we heard an explosion with white smoke and glass falling from the windows," said Maria Concepcion Andrade, 42, who lives on the same block as the Pemex building. "People started running from the building covered in dust. A lot of pieces were flying."